Linking the countries of Sweden and Denmark is the Oresund Bridge which actually comprises a cable-stayed bridge, an artificial island (Peberholm) and a tunnel. The total length is 16km and is split over two levels (a railway is below the road). Marcus Rangell also added: According to what I’ve read, the island is also a biological experiment to see how nature will develop on the island. Currently a bunch of plants have already spread to the island, some are very rare. Thanks: Roland, Thomas, breakbeat, jensflorian, Marcus Rangell, Simone, Yann & Martin